Factors affecting diet selection by sheep. 4. Level of feeding

Abstract

The effects of level of feeding on the potential intake rate and preference shown by sheep for dried forages varying widely in nutritive value was investigated. Intake rate of the forages ranged from 5 to 21.4 g/min when offered for short periods to sheep given 0.8 kg/day of a pelleted ration consisting of 60% lucerne hay and 40% oat grain. When sheep were fed on 0.2 kg/day of pellets, the intake rate of most forages fell slightly, but when feeding level was raised to 1.4 kg/day, the intake rate of all forages declined. The latter depression was only c. 10% for forages that were eaten at a rate of more than 15 g/min by sheep given 0.8 kg/day; but the intake rate of wheaten straw, which was previously eaten at 5 g/min, was depressed by 96%. Level of feeding did not affect the relative preference by sheep for forages which were eaten at rates exceeding 15 g/min. However, calculations indicated that preference for forages with an intake rate of less than 15 g/min would decline as feed intake was raised to the highest level. The results suggest that, for predicting diet selection by sheep, a standardized level of feeding should be adopted when the intake rates of forages are measured.